while hashed public keys protects your coins specifically, they do nothing against the millions of already exposed public keys from which an attacker with an ECDLP break can use to wreak havoc and destroy the value of Bitcoin. Yes, your coins will be safe, but they won't have any value, so what's the point?
that's the killer argument
But it makes the case, IMO, for setting a long (several years perhaps) timescale for invalidating P2PK outputs, giving everyone holding BTC at those pubkeys a chance to move funds to hashed pubkeys.
If you believe that the salient factor is how high the proportion of the supply getting stolen by something (not necessarily a QC either) that can solve the discrete logarithm of an exposed public key, then surely if that vast percentage (is it ~20-25%?) of BTC could be encouraged into hashed public keys,
then your argument that hashed public keys being safe does not hold, assuming that say 90-95% of public keys are kept safe till being spent? What is the real cost to not hashing taproot keys onchain, just saving space?
It's not even just the high proportion, it's also the visibility of some of the coins. In particular, all coins suspected to be Satoshi's are in P2PK outputs. If those moved ever, even to a different sig algo, it would cause enormous chaos. If those are stolen, there would be even more chaos. And those coins are just ~4% of the final money supply. So even if everyone else moved to non-ECDLP keys, the fact that those high profile coins are still secured by ECDLP poses a huge problem.